“This is the wave of the future,” he said Thursday on “CBS This Morning.”

Federal authorities are looking into the possibility that 24-year-old, Kuwait-born Muhammad Youssef Abdulazeez was inspired by the terror group to kill four Marines. If that is the case, Morell said it would be “the most significant ISIS-inspired attack” on U.S. soil to date.

“I think that’s where we’re going to end up here,” Morell said.

At roughly 10:45 am local time, Abdulaeez had the armed services recruiting center under siege.

He pulled into the strip mall in a silver Mustang, fired shots into the facility and then drove off, reports CBS News correspondent Dean Reynolds.

“He didn’t get out the car he didn’t do nothing like that. He shot ten times and then backed up,” witness Keegan Green said. “Then as soon as he backed up, he put ten more in the building.”

A pursuit ensued, as Abdulazeez drove 7 miles to a Naval and Marine reserve center, where he launched a second attack and shot four Marines.

He allegedly plowed through an unmanned barricade, driving close to 100 yards onto the base where he gunned down his victims, before being shot by local law enforcement.

The attack comes in the final days of the holy month of Ramadan, a month in which ISIS followers were urged by the terror group to make “calamities for the nonbelievers.”

Authorities continue to comb for information to determine what motivated Abdulazeez and remain on high alert for ISIS-inspired lone-wolf attackers.

“There have been about 50 to 60 arrests of individuals who are in some way inspired by ISIS in the United States since ISIS became a phenomenon, and those arrests cut across 20 different states,” Morell said.

In May, authorities shot and killed two gunmen who attacked an anti-Islamic event in Garland, Texas. Another self-radicalized man who attacked four rookie officers with a hatchet in New York City was shot and killed by police in October.

Abdulazeez was not on any U.S. terror list and the FBI said they have not found any connections to ISIS or Muslim extremists, but the continued threat of lone-wolf attacks remains a concern for law enforcement.

“You can have a young man who may not be in any contact with a foreign terrorist organization… but who is in his own home, in his bedroom, in his basement, watching videos, going to websites, who is completely self-radicalized without any contact with foreigners or with anybody in the United States,” Morell said.